Ottoman forces under Mehmed II conquer Constantinople
A 53-day siege ends the Byzantine Empire and, by convention, the Middle Ages
Quick facts
- Location
- Constantinople (modern Istanbul)
- Ottoman Sultan
- Mehmed II, age 21
- Byzantine emperor
- Constantine XI Palaiologos
- Siege length
- 53 days
What happened
Constantinople, founded by the Roman emperor Constantine I in 324 and capital of the Byzantine Empire for over a thousand years, had survived sieges, internal rebellions, and even a period of Crusader occupation, protected by fortifications considered the strongest in the medieval world. Ottoman Sultan Mehmed II, just 19 when he took the throne in 1451, spent a year building fortresses along the Bosporus before launching a siege on 6 April 1453, using massive cannons to batter walls that had withstood every previous attacker. After 53 days the city fell on Tuesday 29 May 1453. Mehmed entered the city, called an end to the pillaging, and ordered Hagia Sophia converted from a church into a mosque, a deliberate statement that the city's twelve centuries as a bastion of Christianity had ended.
Why it matters
The fall of Constantinople ended the last direct political continuation of the Roman Empire and gave the Ottomans a capital at the crossroads of Europe and Asia; historians conventionally use the event to mark the end of the Middle Ages in the eastern Mediterranean, both for its finality and because Greek scholars fleeing the city helped accelerate the Renaissance already underway in Italy.
How we know
The siege is documented by multiple eyewitnesses on both sides, including Ottoman court chroniclers and Byzantine and Italian observers present in the city, whose accounts corroborate the siege's length, the use of massed cannon fire against the Theodosian Walls, and the city's fall on 29 May.
Sources
- World History Encyclopedia. 1453: The Fall of Constantinople · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- World History Encyclopedia. 1453: The Fall of Constantinople · Reputable sourceworldhistory.org · The domain "worldhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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Related timelines
- The Byzantine Empire → · The full thousand-year Byzantine story this siege ends, from Constantine's new capital in 324 to Mehmed II's cannons in 1453.